What is Overlays

Service and content delivery over the Internet is currently supported by overlay architectures of different types. There is a trend towards distributed computing and service creation in peer-to-peer and grid networks, which are able to overcome performance bottlenecks of client server architectures. Overlays are deployed for single applications or as multi purpose infrastructure for communities with focus on their special demands. Various overlay structures have also developed on lower network layers. The motivation for those overlays is to bridge or extend one networking technology on top of another in order to build common widespread platforms through heterogeneous telecommunication environments. We address such approaches especially within the standardization of Internet protocols (IP), where the main focus is on evolving techniques on higher layers.